32 
ON THE MESENT£;RIC VEINS. 
intestines, were covered on their internal surfaces with a small 
quantity of mucus and biliary fluid, while the large intestines, 
as the colon and rectum, contained a very small portion of faecal 
matter. I then collected together all the contents of the stomach, 
intestines, and the fluid which had escaped from the thoracic 
duct during this experiment, and found the quantity not more 
than one-third of a pint. 
From this experiment, therefore, it becomes very evident that 
the intestinal absorption of the fluid must have taken place by 
the mesenteric veins to a much greater extent than by the lacteal 
absorbent vessels; and, as a proof of the function of absorption 
and excretion having been carried on, it will also be proper to 
state, that the bladder became filled with urine during this ex¬ 
periment. 
Asa further proof that the real veins do absorb a large portion 
of the fluids which are taken into the stomach and intestinal canal, 
Magendie very justly observes, that there are some persons who 
drink from two to three gallons of mineral waters in a few hours, 
and reject them almost at the same instant by urine. Also, that 
it is impossible for the thoracic duct, from its smallness in size, 
to be enabled to give a sufficient passage to these and the lym¬ 
phatic fluid at the same time.’’ 
We find, likewise, in our veterinary practice, that horses, when 
deprived of water for some time, will, if allowed, drink a very- 
enormous quantity at one time; almost the whole of which, 
instead of remaining in the stomach and small intestines, will 
in place thereof pass directly into the caecum and colon, ftom 
whence it will quickly become absorbed, to be again passed off 
by excretion. 
Now, in such instances as these, it is very evident that the 
extreme rttdicles of the minute branches of the large veins of 
the cacum and colon must, under these circumstances, absorb 
the principal portion of the water admitted into these parts. Be¬ 
sides, from the very great extent of surface for absorption which 
these two intestines present, as weil as the innumerable manner 
in which the radicles of the veins arise "•from the inner surface 
of these parts, also in a very great measure tend to confirm 
that which has been already advanced on the subject. 
It is, I say, very clear, from the great rapidity with which the 
water is absorbed, that this absorption must principally be af¬ 
fected by the extreme radicles of the mesenteric veins. Besides, 
the lacteals are not at all numerous in these parts ; in short, not 
a quarter part so numerous as they are in the small intestines, 
as the jejunum and ileum, from whence by very far the greatest 
quantity and the best portion of the chyle is absorbed from, and 
